Systems that deliver certain drugs to a patient (e.g., targeted to a particular tissue or cell type or targeted to a specific diseased tissue but not normal tissue), or that control release of drugs has long been recognized as beneficial.
For example, therapeutics that include an active drug and that are, e.g., targeted to a particular tissue or cell type or targeted to a specific diseased tissue but not to normal tissue, may reduce the amount of the drug in body tissues that do not require treatment. This is particularly important when treating a condition such as cancer where it is desirable that a cytotoxic dose of the drug is delivered to cancer cells without killing the surrounding non-cancerous tissue. Further, such therapeutics may reduce the undesirable and sometimes life-threatening side effects common in anticancer therapy. In addition, such therapeutics may allow drugs to reach certain tissues they would otherwise be unable to reach.
Delivery of therapeutic nanoparticles can be achieved through parenteral injection of a reconstituted suspension of the nanoparticles. The original nanoparticle suspension is lyophilized, i.e., freeze dried, for storage before reconstitution. Freeze drying a nanoparticle suspension potentially creates a product for reconstitution with far superior storage stability than its frozen suspension counterpart. Further, freeze drying may provide easier storage that may not require constant, very low, temperatures. However, the reconstituted lyophilisate must possess physicochemical and performance attributes that are comparable or superior to the original suspension. Redispersing into particles of the same size without trace particulates due to micro-aggregation or undispersed particles is the most challenging aspect of nanoparticle suspension lyophilization.
Accordingly, a need exists for nanoparticle therapeutics and methods of making such nanoparticles, that are capable of delivering therapeutic levels of drug to treat diseases such as cancer, and possess superior storage capabilities.